Osteoclast number is reduced in baseline patients, but bone resorption activity is increased after TNF-blocker exposure.

<p>A) Representative images of culture day 21 of cells stimulated with M-CSF, RANKL, dexamethasone and TGF-β and stained for TRAP. OC number increased throughout time and at culture day 21 baseline patients have significantly less osteoclasts than healthy donors (p = 0.0038). No differences were found in the number of nuclei per OC in any studied time of culture. B) Representative images of pit assay at culture day 21. Patients at follow-up had significantly higher number of pits and resorption area at culture day 21 when compared to their baseline (p = 0.0469 for both resorption pit number and percentage of resorbed area). Dots represent median counts for each group at each time-point and bars represent interquartile range [10–90]. d—day; OC—osteoclast; Scale bars 100μm, red arrows—osteoclasts, black arrows—resorption pits.